general protection fault in update_sit_entry

Status: moderation: reported on 2026/08/24 03:57
Subsystems: f2fs
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+0204be4854b740e0ca24@syzkaller.appspotmail.com
First crash: 6d10h, last: 6d10h
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
040a2fce assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ✅ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ general protection fault in update_sit_entry 2026/08/22 00:33 2026/08/22 00:33 2026/08/22 01:18 1e72964b
Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 general protection fault in update_sit_entry origin:lts-only 8 syz, C error 18 76d 683d 0/3 upstream: reported C repro on 2024/10/11 17:04
linux-4.14 general protection fault in update_sit_entry f2fs 2 syz, C 9 1270d 1383d 0/1 upstream: reported C repro on 2022/11/12 02:17
android-5-10 general protection fault in update_sit_entry 2 syz, C 60 13d 635d 0/2 upstream: reported C repro on 2024/11/29 11:40
linux-6.1 general protection fault in update_sit_entry origin:lts-only 8 syz, C done 17 215d 596d 0/3 upstream: reported C repro on 2025/01/07 01:40
android-6-1 general protection fault in update_sit_entry origin:downstream 2 syz, C error 44 16d 625d 0/2 upstream: reported C repro on 2024/12/08 18:16
android-5-15 general protection fault in update_sit_entry origin:downstream 2 syz, C 69 21d 640d 0/2 upstream: reported C repro on 2024/11/24 02:28

Sample crash report:
loop0: detected capacity change from 0 to 40427
F2FS-fs (loop0): invalid crc value
F2FS-fs (loop0): f2fs_recover_fsync_data: recovery fsync data, check_only: 1
F2FS-fs (loop0): f2fs_disable_checkpoint starts, unusable: 0
F2FS-fs (loop0): f2fs_disable_checkpoint: call f2fs_write_checkpoint(), meta: 0, node: 0, data: 0
F2FS-fs (loop0): Start checkpoint disabled!
F2FS-fs (loop0): f2fs_disable_checkpoint finishes, err:0
F2FS-fs (loop0): Mounted with checkpoint version = 48b305e6
syz.0.0: attempt to access beyond end of device
loop0: rw=2049, sector=45096, nr_sectors = 128 limit=40427
syz.0.0: attempt to access beyond end of device
loop0: rw=2049, sector=45224, nr_sectors = 128 limit=40427
syz.0.0: attempt to access beyond end of device
loop0: rw=2049, sector=45352, nr_sectors = 128 limit=40427
syz.0.0: attempt to access beyond end of device
loop0: rw=2049, sector=45480, nr_sectors = 128 limit=40427
syz.0.0: attempt to access beyond end of device
loop0: rw=2049, sector=45608, nr_sectors = 128 limit=40427
syz.0.0: attempt to access beyond end of device
loop0: rw=2049, sector=45736, nr_sectors = 128 limit=40427
syz.0.0: attempt to access beyond end of device
loop0: rw=2049, sector=45864, nr_sectors = 128 limit=40427
syz.0.0: attempt to access beyond end of device
loop0: rw=2049, sector=45992, nr_sectors = 128 limit=40427
syz.0.0: attempt to access beyond end of device
loop0: rw=2049, sector=46120, nr_sectors = 128 limit=40427
syz.0.0: attempt to access beyond end of device
loop0: rw=2049, sector=46248, nr_sectors = 128 limit=40427
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
CPU: 0 UID: 0 PID: 5317 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:f2fs_test_and_set_bit fs/f2fs/f2fs.h:3287 [inline]
RIP: 0010:update_sit_entry_for_alloc fs/f2fs/segment.c:2515 [inline]
RIP: 0010:update_sit_entry+0x46a/0x1c00 fs/f2fs/segment.c:2568
Code: 8b 04 24 48 8d 58 18 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 43 2d d4 fd 48 8b 1b 4c 01 f3 48 89 d8 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 fa 14 00 00 44 0f b6 3b 44 89 f8 40 08
RSP: 0018:ffffc9000ecde6f8 EFLAGS: 00010206
RAX: 0000000000000006 RBX: 0000000000000032 RCX: ffff88801f6dcb00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000008 R08: ffffffff9057d237 R09: 1ffffffff20afa46
R10: dffffc0000000000 R11: fffffbfff20afa47 R12: 1ffff1100259b1fc
R13: dffffc0000000000 R14: 0000000000000032 R15: ffff88803de124b2
FS:  00007ff6738fa6c0(0000) GS:ffff88808c533000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd5437b2fb3 CR3: 000000001fc84000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 f2fs_allocate_data_block+0x12c2/0x4060 fs/f2fs/segment.c:3842
 do_write_page+0x13f/0x880 fs/f2fs/segment.c:3982
 f2fs_outplace_write_data+0x11a/0x220 fs/f2fs/segment.c:4058
 f2fs_do_write_data_page+0x1150/0x1540 fs/f2fs/data.c:3025
 f2fs_write_single_data_page+0x9cc/0x1840 fs/f2fs/data.c:3142
 f2fs_write_cache_pages fs/f2fs/data.c:3404 [inline]
 __f2fs_write_data_pages fs/f2fs/data.c:3580 [inline]
 f2fs_write_data_pages+0x1d2e/0x36f0 fs/f2fs/data.c:3618
 do_writepages+0x338/0x560 mm/page-writeback.c:2571
 filemap_writeback mm/filemap.c:387 [inline]
 filemap_fdatawrite_range mm/filemap.c:412 [inline]
 filemap_write_and_wait_range+0x335/0x3f0 mm/filemap.c:684
 f2fs_flush_buffered_write fs/f2fs/file.c:5154 [inline]
 f2fs_file_write_iter+0x841/0x28e0 fs/f2fs/file.c:5373
 iter_file_splice_write+0xa31/0x1240 fs/splice.c:736
 do_splice_from fs/splice.c:936 [inline]
 direct_splice_actor+0x101/0x160 fs/splice.c:1159
 splice_direct_to_actor+0x57b/0xcb0 fs/splice.c:1103
 do_splice_direct_actor fs/splice.c:1202 [inline]
 do_splice_direct+0x195/0x290 fs/splice.c:1228
 do_sendfile+0x52e/0x7c0 fs/read_write.c:1371
 __do_sys_sendfile64 fs/read_write.c:1432 [inline]
 __se_sys_sendfile64+0x144/0x1a0 fs/read_write.c:1418
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff67299e0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff6738f9fe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007ff672c25fa0 RCX: 00007ff67299e0d9
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000004
RBP: 00007ff672a35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000fffe82 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff672c26038 R14: 00007ff672c25fa0 R15: 00007ffdb3b7f718
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:f2fs_test_and_set_bit fs/f2fs/f2fs.h:3287 [inline]
RIP: 0010:update_sit_entry_for_alloc fs/f2fs/segment.c:2515 [inline]
RIP: 0010:update_sit_entry+0x46a/0x1c00 fs/f2fs/segment.c:2568
Code: 8b 04 24 48 8d 58 18 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 43 2d d4 fd 48 8b 1b 4c 01 f3 48 89 d8 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 fa 14 00 00 44 0f b6 3b 44 89 f8 40 08
RSP: 0018:ffffc9000ecde6f8 EFLAGS: 00010206
RAX: 0000000000000006 RBX: 0000000000000032 RCX: ffff88801f6dcb00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000008 R08: ffffffff9057d237 R09: 1ffffffff20afa46
R10: dffffc0000000000 R11: fffffbfff20afa47 R12: 1ffff1100259b1fc
R13: dffffc0000000000 R14: 0000000000000032 R15: ffff88803de124b2
FS:  00007ff6738fa6c0(0000) GS:ffff88808c533000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffdb3b7ef40 CR3: 000000001fc84000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess):
   0:	8b 04 24             	mov    (%rsp),%eax
   3:	48 8d 58 18          	lea    0x18(%rax),%rbx
   7:	48 89 d8             	mov    %rbx,%rax
   a:	48 c1 e8 03          	shr    $0x3,%rax
   e:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1)
  13:	74 08                	je     0x1d
  15:	48 89 df             	mov    %rbx,%rdi
  18:	e8 43 2d d4 fd       	call   0xfdd42d60
  1d:	48 8b 1b             	mov    (%rbx),%rbx
  20:	4c 01 f3             	add    %r14,%rbx
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 0f b6 04 28       	movzbl (%rax,%r13,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	0f 85 fa 14 00 00    	jne    0x1531
  37:	44 0f b6 3b          	movzbl (%rbx),%r15d
  3b:	44 89 f8             	mov    %r15d,%eax
  3e:	40                   	rex
  3f:	08                   	.byte 0x8

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/20 03:47 upstream bd5f485f3f02 1e72964b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root general protection fault in update_sit_entry
* Struck through repros no longer work on HEAD.